AAO Starbugs: software control and associated algorithms

The Australian Astronomical Observatory's TAIPAN instrument deploys 150 Starbug robots to position optical fibres to accuracies of 0.3 arcsec, on a 32 cm glass field plate on the focal plane of the 1.2 m UK-Schmidt telescope. This paper describes the software system developed to control and monitor the Starbugs, with particular emphasis on the automated path-finding algorithms, and the metrology software which keeps track of the position and motion of individual Starbugs as they independently move in a crowded field. The software employs a tiered approach to find a collision-free path for every Starbug, from its current position to its target location. This consists of three path-finding stages of increasing complexity and computational cost. For each Starbug a path is attempted using a simple method. If unsuccessful, subsequently more complex (and expensive) methods are tried until a valid path is found or the target is flagged as unreachable.Comment: 10 pages, to be published in Proc. SPIE 9913, Software and Cyberinfrastructure for Astronomy IV; 201

Characterization of low pathogenic H5 subtype influenza viruses from Eurasia: Implications for the origin of highly pathogenic H5N1 viruses

Oral Presentations - Genetic and Antigenic EvolutionHighly pathogenic avian influenza (HPAI) H5N1 viruses are now endemic in many Asian countries. The immediate precursor of these HPAI viruses was recognized as A/Goose/Guangdong/1/96 (Gs/Gd)-like H5N1 HPAI viruses first detected in Guangdong in 1996. However, precursors of the Gs/GD-like viruses and their subsequent reassortants have not been fully determined. Here we characterize low pathogenic avian influenza (LPAI) H5 subtype viruses isolated from poultry and migratory birds in southern China and Europe from the 1970s to the 2000s. Phylogenetic analyses revealed that Gs/GD-like virus was likely derived from an LPAI H5 virus in migratory birds. However, its variants arose from multiple reassortments between Gs/GD-like virus and viruses from migratory birds, or with those Eurasian viruses isolated in the 1970s. It is of note that unlike HPAI H5N1 viruses, those recent LPAI H5 viruses have not become established in aquatic or terrestrial poultry. Phylogenetic analyses revealed the dynamic nature of the influenza gene pool in Eurasia with repeated transmissions between the eastern and western extremities of the continent. The data also shows reassortment between influenza viruses from domestic and migratory birds in this region that has contributed to the expanded diversity of the influenza gene pool among poultry in Eurasia ...postprin

Characterization of H3N2 influenza viruses isolated from pigs in southern China

Poster Presentations: Animal Influenza EcologyHuman-like H3N2 influenza viruses have repeatedly transmitted to domestic pigs in different regions of the world, but it is still not certain whether any of those variants have become established in pig populations. The detection of different subtypes of avian influenza viruses from pigs makes it an ideal candidate for the genesis of a possible reassortant virus with both human and avian gene segments. However, whether pigs could act as a “mixing vessel” for a possible pandemic virus remains unanswered. Long-term influenza surveillance in pigs in southern China revealed that H3N2 influenza viruses were regularly detected from domestic pigs from 1998 to 2003. Antigenic analysis of representative strains revealed that two distinguishable groups of H3N2 influenza viruses were present in pigs during this period: a contemporary human-like viruses (represented by Sydney/5/97), and Port Chalmers/1/73-like (PC-like) viruses. Phylogenetic analysis of the representative strains confirmed those two groups. In general, the PC-like viruses were most closely related to those H3N2 reassortants recognized from European pigs since the mid-1980s, while the remaining isolates were most closely related to those contemporary human H3N2 viruses. It is interesting to note that one PC-like isolate contained a classical swine H1N1-like NP gene, Sw/HK/1197/02, suggesting that after introduction to pigs in southern China the European swine H3N2 virus further reassorted with local swine virus. The contemporary humanlike H3N2 viruses isolated from pig appeared to have resulted from repeated introduction from humans to pigs. Interestingly, one isolate (Sw/HK/NS1128/03) clustered with those human isolates detected in the early 1990s. These findings suggesting that some recent human H3N2 variants may be maintained long-term in pig populations in southern China. The present study provides updated information on the role of pigs in the interspecies transmission and genetic reassortment of influenza viruses in this region.postprin

The Incidental Matters Rule and Judicially Created Exceptions to the Nebraska Public Meetings Law: A Call to the Legislature in \u3ci\u3eMeyer v. Board of Regents\u3c/i\u3e, 510 N.W.2d 450 (Neb. App. 1993)

This Note first addresses the facts of the Nebraska Court of Appeals decision in Meyer v. Board of Regents and then generally discusses the Nebraska Public Meetings Law. Specific holdings of Meyer are critiqued. The final parts of this Note consist of two features. First, in order to assist practitioners, the author suggests procedures for public entity negotiations that should avoid most Nebraska Public Meetings Law violations. Second, the author suggests that the holding in Meyer can best be explained by the court\u27s concern for the real-world consequences and dangerous precedential value that would have been set if the court would have invalidated the actions taken by the Board of Regents. In the final analysis, such result-oriented decision making is criticized, and the Nebraska Legislature is invited to take appropriate corrective action

GNOSIS: the first instrument to use fibre Bragg gratings for OH suppression

GNOSIS is a prototype astrophotonic instrument that utilizes OH suppression fibres consisting of fibre Bragg gratings and photonic lanterns to suppress the 103 brightest atmospheric emission doublets between 1.47-1.7 microns. GNOSIS was commissioned at the 3.9-meter Anglo-Australian Telescope with the IRIS2 spectrograph to demonstrate the potential of OH suppression fibres, but may be potentially used with any telescope and spectrograph combination. Unlike previous atmospheric suppression techniques GNOSIS suppresses the lines before dispersion and in a manner that depends purely on wavelength. We present the instrument design and report the results of laboratory and on-sky tests from commissioning. While these tests demonstrated high throughput and excellent suppression of the skylines by the OH suppression fibres, surprisingly GNOSIS produced no significant reduction in the interline background and the sensitivity of GNOSIS and IRIS2 is about the same as IRIS2. It is unclear whether the lack of reduction in the interline background is due to physical sources or systematic errors as the observations are detector noise-dominated. OH suppression fibres could potentially impact ground-based astronomy at the level of adaptive optics or greater. However, until a clear reduction in the interline background and the corresponding increasing in sensitivity is demonstrated optimized OH suppression fibres paired with a fibre-fed spectrograph will at least provide a real benefits at low resolving powers.Comment: 15 pages, 13 figures, accepted to A

Multiwavelength observations of the M15 intermediate velocity cloud

We present Westerbork Synthesis Radio Telescope HI images, Lovell Telescope multibeam HI wide-field mapping, Wisconsin H-alpha Mapper facility images, William Herschel Telescope longslit echelle CaII observations, and IRAS ISSA 60 and 100 micron coadded images towards the intermediate velocity cloud located in the general direction of the M15 globular cluster. When combined with previously-published Arecibo data, the HI gas in the IVC is found to be clumpy, with peak HI column density of 1.5x10^(20) cm^(-2), inferred volume density (assuming spherical symmetry) of 24 cm^(-3)/(D kpc), and maximum brightness temperature at a resolution of 81x14 arcsec of 14 K. The HI gas in the cloud is warm, with a minimum FWHM value of 5 km/s, corresponding to a kinetic temperature, in the absence of turbulence, of 540 K. There are indications in the HI data of 2-component velocity structure in the IVC, indicative of cloudlets. This velocity structure is also tentatively seen in the CaK spectra, although the SNR is low. The main IVC condensation is detected by WHAM in H-alpha with intensities uncorrected for Galactic absorption of upto 1.3 Rayleigh, indicating that the cloud is partially ionised. The FWHM of the ionised component, at a resolution of 1 degree, exceeds 30 km/s. The spatial and velocity coincidence of the H-alpha and HI peaks in emission is qualitatively good. Finally, the 100 and 60 micron IRAS images show spatial coincidence over a 0.7 degree field, with low and intermediate-velocity gas, respectively, indicating that the IVC may contain dust.Comment: MNRAS, in pres